There's only about 200v coming off the power supply B+ out, and the schematic calls for 250-280v depending on which one I'm looking at. There are also corresponding lowered values around the PC 6 board, which I expect may be a result of the upstream issue.

Seems odd tho, that the same power supply / hookups to the old PC 6 didn't manifest any issues with output...

are you using the v14 regulated power supply? stock power supply, standard upgrade power supply, or v13 regulated supply none of them will work,you need the higher current rating of v14 (or newest v17) power supply, that's why ALL of your B+ voltages are low, and probably extremely low filament voltage.My PAS upgrades are now sold by TubeNirvana, check here. . . . . http://www.tubenirvana.net/pas3-power-supplies.html